channels: Add originator to ssh_channel_accept

Added API function ssh_channel_open_forward_port that is the same as
ssh_channel_accept_forward with the addition to determine the
originator address and port

Signed-off-by: Tomas Holmqvist <tomhol@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>

doc/forwarding.dox

@@ -165,6 +165,8 @@ int web_server(ssh_session session)
   char buffer[256];
   int nbytes, nwritten;
   int port = 0;
+  char *peer_address = NULL;
+  int peer_port = 0;
   char *helloworld = ""
 "HTTP/1.1 200 OK\n"
 "Content-Type: text/html\n"
@@ -187,7 +189,8 @@ int web_server(ssh_session session)
     return rc;
   }
 
-  channel = ssh_channel_accept_forward(session, 60000, &port);
+  channel = ssh_channel_open_forward_port(session, 60000, &port, 
+                                        &peer_address, &peer_port);
   if (channel == NULL)
   {
     fprintf(stderr, "Error waiting for incoming connection: %s\n",
@@ -204,6 +207,7 @@ int web_server(ssh_session session)
               ssh_get_error(session));
       ssh_channel_send_eof(channel);
       ssh_channel_free(channel);
+      ssh_string_free_char(peer_address);
       return SSH_ERROR;
     }
     if (strncmp(buffer, "GET /", 5)) continue;
@@ -216,13 +220,15 @@ int web_server(ssh_session session)
               ssh_get_error(session));
       ssh_channel_send_eof(channel);
       ssh_channel_free(channel);
+      ssh_string_free_char(peer_address);
       return SSH_ERROR;
     }
-    printf("Sent answer\n");
+    printf("Sent answer to %s:%d\n", peer_address, peer_port);
   }
 
   ssh_channel_send_eof(channel);
   ssh_channel_free(channel);
+  ssh_string_free_char(peer_address);
   return SSH_OK;
 }
 @endcode

include/libssh/libssh.h

@@ -510,7 +510,12 @@ LIBSSH_API char *ssh_dirname (const char *path);
 LIBSSH_API int ssh_finalize(void);
 
 /* REVERSE PORT FORWARDING */
-LIBSSH_API ssh_channel ssh_channel_accept_forward(ssh_session session,
+LIBSSH_API ssh_channel ssh_channel_open_forward_port(ssh_session session,
+                                                   int timeout_ms,
+                                                   int *destination_port,
+                                                   char **originator,
+                                                   int *originator_port);
+SSH_DEPRECATED LIBSSH_API ssh_channel ssh_channel_accept_forward(ssh_session session,
                                                   int timeout_ms,
                                                   int *destination_port);
 LIBSSH_API int ssh_channel_cancel_forward(ssh_session session,

src/channels.c

@@ -29,6 +29,7 @@
 #include <errno.h>
 #include <time.h>
 #include <stdbool.h>
+#include <string.h>
 #ifdef HAVE_SYS_TIME_H
 #include <sys/time.h>
 #endif /* HAVE_SYS_TIME_H */
@@ -2135,7 +2136,7 @@ error:
 }
 
 static ssh_channel ssh_channel_accept(ssh_session session, int channeltype,
-    int timeout_ms, int *destination_port) {
+    int timeout_ms, int *destination_port, char **originator, int *originator_port) {
 #ifndef _WIN32
   static const struct timespec ts = {
     .tv_sec = 0,
@@ -2169,6 +2170,12 @@ static ssh_channel ssh_channel_accept(ssh_session session, int channeltype,
           if(destination_port) {
             *destination_port=msg->channel_request_open.destination_port;
           }
+          if(originator) {
+            *originator=strdup(msg->channel_request_open.originator);
+          }
+          if(originator_port) {
+            *originator_port=msg->channel_request_open.originator_port;
+          }
 
           ssh_message_free(msg);
           return channel;
@@ -2200,7 +2207,7 @@ static ssh_channel ssh_channel_accept(ssh_session session, int channeltype,
  *                      the server.
  */
 ssh_channel ssh_channel_accept_x11(ssh_channel channel, int timeout_ms) {
-  return ssh_channel_accept(channel->session, SSH_CHANNEL_X11, timeout_ms, NULL);
+  return ssh_channel_accept(channel->session, SSH_CHANNEL_X11, timeout_ms, NULL, NULL, NULL);
 }
 
 /**
@@ -2454,11 +2461,11 @@ int ssh_forward_listen(ssh_session session, const char *address, int port, int *
 
 /* DEPRECATED */
 ssh_channel ssh_forward_accept(ssh_session session, int timeout_ms) {
-  return ssh_channel_accept(session, SSH_CHANNEL_FORWARDED_TCPIP, timeout_ms, NULL);
+  return ssh_channel_accept(session, SSH_CHANNEL_FORWARDED_TCPIP, timeout_ms, NULL, NULL, NULL);
 }
 
 /**
- * @brief Accept an incoming TCP/IP forwarding channel and get information
+ * @brief Accept an incoming TCP/IP forwarding channel and get some information
  * about incomming connection
  * @param[in]  session    The ssh session to use.
  *
@@ -2470,7 +2477,30 @@ ssh_channel ssh_forward_accept(ssh_session session, int timeout_ms) {
  *         the server
  */
 ssh_channel ssh_channel_accept_forward(ssh_session session, int timeout_ms, int* destination_port) {
-  return ssh_channel_accept(session, SSH_CHANNEL_FORWARDED_TCPIP, timeout_ms, destination_port);
+  return ssh_channel_accept(session, SSH_CHANNEL_FORWARDED_TCPIP, timeout_ms, destination_port, NULL, NULL);
+}
+
+/**
+ * @brief Accept an incoming TCP/IP forwarding channel and get information
+ * about incomming connection
+ * @param[in]  session    The ssh session to use.
+ *
+ * @param[in]  timeout_ms A timeout in milliseconds.
+ *
+ * @param[out]  destination_port A pointer to destination port or NULL.
+ *
+ * @param[out]  originator A pointer to a pointer to a string of originator host or NULL.
+ *              That the caller is responsible for to ssh_string_free_char().
+ *
+ * @param[out]  originator_port A pointer to originator port or NULL.
+ *
+ * @return Newly created channel, or NULL if no incoming channel request from
+ *         the server
+ *
+ * @see ssh_string_free_char()
+ */
+ssh_channel ssh_channel_open_forward_port(ssh_session session, int timeout_ms, int *destination_port, char **originator, int *originator_port) {
+  return ssh_channel_accept(session, SSH_CHANNEL_FORWARDED_TCPIP, timeout_ms, destination_port, originator, originator_port);
 }
 
 /**

tests/client/torture_forward.c

@@ -82,6 +82,8 @@ static void torture_ssh_forward(void **state)
     ssh_channel c;
     int dport;
     int bound_port;
+    char *originator_host = NULL;
+    int originator_port;
     int rc;
     int verbosity = SSH_LOG_TRACE;
 
@@ -90,7 +92,7 @@ static void torture_ssh_forward(void **state)
     rc = ssh_channel_listen_forward(session, "127.0.0.21", 8080, &bound_port);
     assert_ssh_return_code(session, rc);
 
-    c = ssh_channel_accept_forward(session, 10, &dport);
+    c = ssh_channel_open_forward_port(session, 10, &dport, &originator_host, &originator_port);
     /* We do not get a listener and run into the timeout here */
     assert_null(c);